No Effect of Carbohydrate-Protein on Cycling Performance and Indices of Recovery
ABSTRACT The aim of this study was to determine whether adding protein to a CHO beverage would improve late-exercise cycle time-trial performance over CHO alone. Furthermore, we examined the effects of coingesting protein with CHO during exercise on postexercise markers of sarcolemmal disruption and the recovery of muscle function.
In a double-blind, crossover design, 12 trained male cyclists performed 120 min of steady-state (SS) cycling at approximately 55% VO2max followed by a time trial lasting approximately 1 h. At 15-min intervals during SS exercise, participants consumed either a CHO or a CHO + protein (CHO + Pro) beverage (providing 65 g x h(-1) CHO or 65 g x h(-1) CHO plus 19 g x h(-1) protein). Twenty-four hours after the onset of the SS cycle, participants completed a maximum isometric strength test. At rest and 24 h postexercise, a visual analog scale was used to determine lower-limb muscle soreness, and blood samples were obtained for plasma creatine kinase concentration. Dietary control was implemented 24 h before and during the time course of each trial.
Average power output sustained during time trial was similar for CHO and CHO + Pro, with no effect of treatment on the time to complete the time trial (60:13 +/- 1:33 and 60:51 +/- 2:40 (min:s) for CHO and CHO + Pro, respectively). Postexercise isometric strength significantly declined for CHO (15% +/- 3%) and CHO + Pro (11% +/- 3%) compared with baseline (486 +/- 28 N). Plasma creatine kinase concentrations, and visual analog scale soreness significantly increased at 24 h postexercise, with no difference between treatments.
The present findings suggest that CHO + Pro coingestion during exercise does not improve late-exercise time-trial performance, ameliorate markers of sarcolemmal disruption, or enhance the recovery of muscle function at 24 h postexercise over CHO alone.
Full-textDOI: · Available from: Asker Jeukendrup, Mar 31, 2014
- SourceAvailable from: Vitor Hugo Teixeira
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- "There is already a strong body of scientific evidence showing that the simultaneous ingestion of CHO and protein may attenuate muscle damage (Baty et al., 2007; Bird et al., 2006; Cockburn et al., 2008, 2010; Doyle et al., 1993; Luden et al., 2007; Pritchett et al., 2009; Romano-Ely et al., 2006; Samadi et al., 2012; Saunders et al., 2004, 2007, 2009; Skillen et al., 2008; Valentine et al., 2008), suggesting that the combination of these two macronutrients can be a valuable strategy. However, some studies (Breen et al., 2010; Green et al., 2008; White et al., 2008; Wojcik et al., 2001) do no support these findings. The possible reasons for these discrepancies are (i) the inherent inter-individual variability for indirect systemic markers of muscle damage, namely CK (Betts & Williams, 2010), which was the only blood parameter used to assess muscle damage in the four studies that did not find positive results, and (ii) the different exercise protocols applied. "
ABSTRACT: Abstract Exhaustive or unaccustomed intense exercise can cause exercise-induced muscle damage (EIMD) and its undesirable consequences may decrease the ability to exercise and to adhere to a training programme. This review briefly summarises the muscle damage process, focusing predominantly on oxidative stress and inflammation as contributing factors, and describes how nutrition may be positively used to recover from EIMD. The combined intake of carbohydrates and proteins and the use of antioxidants and/or anti-inflammatory nutrients within physiological ranges are interventions that may assist the recovery process. Although the works studying food instead of nutritional supplements are very scarce, their results seem to indicate that food might be a favourable option as a recovery strategy. To date, the only tested foods were milk, cherries, blueberries and pomegranate with promising results. Other potential solutions are foods rich in protein, carbohydrates, antioxidants and/or anti-inflammatory nutrients.International Journal of Food Sciences and Nutrition 11/2013; DOI:10.3109/09637486.2013.849662 · 1.20 Impact Factor
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- "However, muscle function probably offers the most valid assessment of muscle damage (Clarkson & Hubal, 2002) and is also more relevant than CK in an applied setting. Cockburn et al. (2008) reported recovery of peak torque of the knee flexors to be improved following co-ingestion of carbohydrate and protein compared with carbohydrate alone but other studies suggest that the inclusion of protein to carbohydrate had no effect on recovery of muscle function (Betts et al., 2009; Breen, Tipton, & Jeukendrup, 2010; Green et al., 2008; White et al., 2008; Wojcik et al., 2001). The total protein and carbohydrate ingested in these studies has varied from 23 and 75 g, of protein and carbohydrate, respectively (White et al., 2008) up to 165 and 492 g (Betts et al., 2009). "
ABSTRACT: In this study, we investigated the effect of ingesting carbohydrate alone or carbohydrate with protein on functional and metabolic markers of recovery from a rugby union-specific shuttle running protocol. On three occasions, at least one week apart in a counterbalanced order, nine experienced male rugby union forwards ingested placebo, carbohydrate (1.2 g · kg body mass(-1) · h(-1)) or carbohydrate with protein (0.4 g · kg body mass(-1) · h(-1)) before, during, and after a rugby union-specific protocol. Markers of muscle damage (creatine kinase: before, 258 ± 171 U · L(-1) vs. 24 h after, 574 ± 285 U · L(-1); myoglobin: pre, 50 ± 18 vs. immediately after, 210 ± 84 nmol · L(-1); P < 0.05) and muscle soreness (1, 2, and 3 [maximum soreness = 8] for before, immediately after, and 24 h after exercise, respectively) increased. Leg strength and repeated 6-s cycle sprint mean power were slightly reduced after exercise (93% and 95% of pre-exercise values, respectively; P < 0.05), but were almost fully recovered after 24 h (97% and 99% of pre-exercise values, respectively). There were no differences between trials for any measure. These results indicate that in experienced rugby players, the small degree of muscle damage and reduction in function induced by the exercise protocol were not attenuated by the ingestion of carbohydrate and protein.Journal of Sports Sciences 09/2011; 29(12):1253-62. DOI:10.1080/02640414.2011.587194 · 2.10 Impact Factor
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ABSTRACT: This review considers aspects of the optimal nutritional strategy for recovery from prolonged moderate to high intensity exercise. Dietary carbohydrate represents a central component of post-exercise nutrition. Therefore, carbohydrate should be ingested as early as possible in the post-exercise period and at frequent (i.e. 15- to 30-minute) intervals throughout recovery to maximize the rate of muscle glycogen resynthesis. Solid and liquid carbohydrate supplements or whole foods can achieve this aim with equal effect but should be of high glycaemic index and ingested following the feeding schedule described above at a rate of at least 1 g/kg/h in order to rapidly and sufficiently increase both blood glucose and insulin concentrations throughout recovery. Adding ≥0.3 g/kg/h of protein to a carbohydrate supplement results in a synergistic increase in insulin secretion that can, in some circumstances, accelerate muscle glycogen resynthesis. Specifically, if carbohydrate has not been ingested in quantities sufficient to maximize the rate of muscle glycogen resynthesis, the inclusion of protein may at least partially compensate for the limited availability of ingested carbohydrate. Some studies have reported improved physical performance with ingestion of carbohydrate-protein mixtures, both during exercise and during recovery prior to a subsequent exercise test. While not all of the evidence supports these ergogenic benefits, there is clearly the potential for improved performance under certain conditions, e.g. if the additional protein increases the energy content of a supplement and/or the carbohydrate fraction is ingested at below the recommended rate. The underlying mechanism for such effects may be partly due to increased muscle glycogen resynthesis during recovery, although there is varied support for other factors such as an increased central drive to exercise, a blunting of exercise-induced muscle damage, altered metabolism during exercise subsequent to recovery, or a combination of these mechanisms.Sports Medicine 11/2010; 40(11):941-59. DOI:10.2165/11536900-000000000-00000 · 5.32 Impact Factor